Lane keeping assist system (LKAS) is a system that controls a traveling vehicle to prevent lane deviation of the vehicle when the vehicle is expected to move out of its lane on the basis of its driving information and road information.
A related art LKAS control method includes finding a distance and an angle between a vehicle and a lane using lane information obtained from an imaging device equipped in the vehicle, calculating a lane deviation speed using a traveling direction and speed of the vehicle which is obtained from CAN data of the vehicle, and giving a warning of lane deviation or performing steering control depending on whether the vehicle is out of the lane.
However, the related art control method has a problem in that a control amount is calculated with only a deviation distance and a deviation angle that is an angle between a host vehicle and its lane and thus a controller sensitively operates over a threshold of the lane deviation speed even when the deviation angle is slightly formed. Also, the related art control method uses an experience-based steering torque map to calculate the control amount, and thus can not ensure robustness of control performance against disturbance such as cross wind, road gradient, etc.
There have been proposals for solving these problems by estimating and compensating for expected vehicle behaviors or variables, which however are very sensitive to an error of a camera signal and also have a complicated control algorithm. Thus, the control performance is not expected to be enhanced.